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Foot Sore

Top Horse explains all about laminitis and why prevention is better than cure!

What is laminitis?

Laminitis is a breakdown of internal hoof structures called the ‘laminae’...inflammation (itis) of the sensitive laminae (lamin). There’s two laminae in the hoof...the insensitive laminae is attached to the hoof wall while the sensitive laminae is attached to the pedal bone (also known as the coffin bone). These laminae keep the pedal bone suspended within the hoof while allowing the hoof wall to grow.

Laminitis is very painful for horses...imagine jamming the tips of your fingers in a door and having to do a handstand with all your weight on them. The inflammation hurts like crazy because your fingernails (like a horse’s hoof wall) can’t expand to accommodate the swelling.

What about founder, isn’t it the same thing?

Sort of...while laminitis refers to inflammation of the laminae, it can progress to where it breaks down, allowing the pedal bone to tear away from the hoof wall and once loose, can rotate to either side or ‘sink’ downwards under the horse’s weight where it compresses the sole (see diagrams next page). Founder is a nautical term meaning ‘to sink’.

horse can have laminitis but not progress to founder, whereas a horse that founders will always have first gone through the laminitis stage.

What are the symptoms of laminitis?

One of the best clues is watching the horse go across soft, even ground and compare it to walking on a hard surface. Horses with sensitivity in the feet will shorten up on the harder terrain. Front feet bear 50% more weight than the rear so in most cases they hurt more. Since both feet are sore, the horse doesn’t really limp but steps slowly with short strides.

When the founder is moderate to severe, he will attempt to get weight off his front feet when just standing by:

Shifting weight back and forth on the front feet (paddling).

• Stand with his front feet propped out in front of him while leaning back on his rear legs.

• As the pain worsens he may start spending a lot of time lying down.

• Stiffness.

• Heat in the hooves, especially near the coronet.

This poor pony has laminitis and is standing to try and relive pressure on his hooves.

What causes laminitis and founder?

This is the subject of much discussion and on-going research! Some known causes include poor digestion–if this isn’t working properly, toxins can be released, damaging blood vessels and causing inflammation, including to the laminae. This can be triggered by rich grass, especially during Spring, or a horse on previously sparse pasture suddenly having access to abundant grass. But don’t be fooled into thinking horses only founder during Spring! Watch out for any drought area after rain as horses will relish pigging out on the new green growth.

It’s been estimated around 50-60% of laminitis cases are pasture related.

It's been estimated around 50-60% of laminitis cases are pasture related.

A possible cause are fructans, which are carbohydrate molecules used by plants to store energy. Horses can’t digest fructans so they ferment in the gut, releasing toxins which can lead to colic and laminitis.

Fructans are stored in the plant’s stems and are more concentrated when the grass is stressed during drought, frost or over-grazing. Levels of fructans vary during the day so if your horse is prone to founder, the following can reduce the risk:

• Fructan content is highest during the day, so turn horses out late at night and bring them in mid-morning.

• Avoid grazing paddocks that have been cut for hay as the remaining stems will have a high fructan content.

• Avoid grazing on pasture that has been exposed to frost and bright sunlight as the fructan content will be high.

• Soak all hay (both grass and lucerne) for 60 minutes in lukewarm water, then air-dry it before feeding as this has been shown to reduce fructan content by up to 30%.

Other causes of laminitis can include:

• Carbohydrate overload, eg. a horse gorging on grain feed.

• Overweight horses, especially ponies.

• ‘Road founder’, when horses are worked excessively on hard ground.

• Severe lameness in one foot causing a horse to bear all his weight on the other foot.

• High fever and illness.

• Hooves exposed to very hot ground. Some horses who survived the Victorian Black Saturday bushfires earlier this year were more prone to laminitis after escaping through flames.

• Colic and diarrhoea can also lead to founder.

Are certain breeds more likely to get founder?

No, any horse can get it! Some native ponies are more prone to laminitis due to something called insulin resistance, which is similar to type 2 diabetes in humans. Insulin resistance can be suspected when the fat forms in the following pattern...a hard, cresty neck; fat dimples, fatty deposits around the eyes, sheath, shoulders and tail. Other signs include excessive drinking and urination. Any pony you suspect might be insulin resistant should have their diet very closely monitored as any increase in their food could cause laminitis. Ponies that are ‘good doers’ (ones that need little feed to maintain or gain weight) may be prone to insulin resistance.

If you’re concerned, get the vet to do a blood test on your horse to check for high insulin. It’s not fatal, but horses with high insulin will need their diets closely monitored to prevent laminitis. As with humans, diet and exercise are the best ways to manage insulin resistance; exercise means excess glucose is used.

As this is an article about laminitis, we won’t go into insulin resistance too much, but if you suspect your horse might have it, do an internet search or ask any horse experts you know for advice.

Laminitis is not limited to ponies though...some strains of Thoroughbreds, Arabians, Quarterhorses, Morgans and heavy Draught breeds are prone to laminitis but as mentioned, given the right conditions, any horse can come down with it.

How does laminitis and founder progress?

There are a few stages...the first is when one of the triggers mentioned causes the laminae to start separating and this can be painless for the first few days. Going back to bushfire-affected horses, laminitis can be triggered by the horse galloping through flames, causing the hooves to heat although symptoms didn’t show until days later. The same happens with horses gorging on grain or abundant grass...symptoms might not appear until a few days down the track.

If you suspect your horse has been exposed to a potential laminitis situation, you can reduce the chance of him foundering by frequently bathing all four of his feet in cold water (water restrictions permitting) or better still, having the horse stand in cold, icy water up to around the middle of the cannon bones before symptoms appear.

Keep ice floating in the water and top it up whenever it melts. Do this for around 20 minutes with rest periods in between for at least the first 48-72 hours...no longer as this can soften the foot too much which would be counter-productive.
Buckets are ideal but you can also use tyres or railway sleepers lined with plastic or canvas. Some enterprising horse owners make their own foot baths using childrens’ shallow swimming pools.

The acute (founder) phase takes place around 48 hours after the first signs of pain appearing, when the coffin bone detaches and starts to move within the hoof BUT if you can catch and treat laminitis in the first stage, chances are you can prevent this happening.

The chronic stage is when physical changes have taken place within the hoof–in the most severe cases, the coffin bone protrudes through the sole of the foot and the hoof wall can shed and this is called a ‘sinker’.

If your horse has a weight problem, you can restrict his food intake by using a grazing muzzle.

How do you treat founder?

Rule 1...as soon as you notice symptoms or even suspect laminitis, GET THE VET IMMEDIATELY. Early treatment can prevent it developing into a chronic case of founder.

While you’re waiting for the vet, it’s important to apply cold water therapy and do this as much as possible for the first 48 hours. This will help slow down the inflammation happening inside the hoof.

Encourage the horse to move around on level ground as much as possible, which helps circulation which in turn will encourage healing. While you’re waiting for the vet, find a good farrier who specialises in laminitis and barefoot trimming but if you don’t know any, ask around on the horsey internet forums for any in your area.

If you suspect the laminitis has been caused by diet, remove the horse from the source, but don’t stop feeding him altogether...the damage has already been done. Offer him grass hay and water but soak the hay first to remove the fructans.

The vet will give your horse pain-killers to make him more comfortable and may x-ray the feet to assess the damage. He will also administer drugs and drenches, depending on the likely cause.

Let your horse have access to a yard or stable with soft footing so he can free exercise. The soft surface will also encourage him to lie down, relieving the pain.

How can I prevent laminitis?

Weight control is one way, as is being aware of other contributing factors such as grazing hazards (eg. fructan levels in grass). Be on the lookout for possible causes mentioned here and remember that if your horse is exposed to one of them, you can greatly reduce the chances of it progressing to founder by soaking his hooves in icy water.

Other preventative measures are just good basic horse-keeping:

• Restrict your horse’s access to grass by using a grazing muzzle.

• Never make any sudden changes to your horse’s diet.

• Avoid cereal grain-based feeds.

• Limiting overweight ponies access to feed–this is an article in itself so ask an experienced horse person for advice.

• Avoid feeding excess starch and sugars, eg. bread and molasses.

• Regular exercise to utilize excess glucose.

• Give your horse unlimited access to a mineral lick to help balance things and also consider feeding a vitamin and mineral supplement containing biotin, which is a hoof strengthener.

If my horse founders, will he ever be sound again?

If you catch and treat laminitis in the early stages, then probably. If it’s progressed to acute or chronic founder, then it’s hard to say for sure as each case is different and depends on how much the pedal bone has rotated or dropped, but treatment has come a long way in the past few years and with the help of a good vet and specialist farrier, the chances are promising.